Re: [PATCH v9 1/6] misc: Add support for LAN966x PCI device

["Arnd Bergmann" <arnd@arndb.de>]

On Fri, Nov 29, 2024, at 09:10, Herve Codina wrote:
> Hi Michal,
> On Thu, 28 Nov 2024 20:42:53 +0100
> Michal Kubecek <mkubecek@suse.cz> wrote:
>> > --- a/drivers/misc/Kconfig
>> > +++ b/drivers/misc/Kconfig
>> > @@ -610,6 +610,30 @@ config MARVELL_CN10K_DPI
>> >  	  To compile this driver as a module, choose M here: the module
>> >  	  will be called mrvl_cn10k_dpi.
>> >  
>> > +config MCHP_LAN966X_PCI
>> > +	tristate "Microchip LAN966x PCIe Support"
>> > +	depends on PCI
>> > +	select OF
>> > +	select OF_OVERLAY  
>> 
>> Are these "select" statements what we want? When configuring current
>> mainline snapshot, I accidentally enabled this driver and ended up
>> flooded with an enormous amount of new config options, most of which
>> didn't make much sense on x86_64. It took quite long to investigate why.
>> 
>> Couldn't we rather use
>> 
>> 	depends on PCI && OF && OF_OVERLAY
>> 
>> like other drivers?

Agreed.

I would write in two lines as

        depends on PCI
        depends on OF_OVERLAY

since OF_OVERLAY already depends on OF, that can be left out.
The effect is the same as your variant though.
 
>
> I don't have a strong opinion on this 'select' vs 'depends on' for those
> symbols.
>
> I used select because the dependency is not obvious for a user that just
> want the driver for the LAN966x PCI device.

The general rules for picking one over the other are:

- use 'select' for symbols that can not be enabled manually
- prefer 'depends on' for user-visible options
- do whatever other driver do for the same symbol, to avoid
  dependency loops.

     Arnd